What is the purpose of a subnet mask?

Asubnet maskis a 32-bit number used in IP networking to divide an IP address into network and host portions. This division is crucial for routing traffic within and between networks. The subnet mask works in tandem with the IP address to identify which part of the address refers to the network and which part refers to the host. This distinction allows for efficient IP address allocation and routing.​

For example, in the IP address 192.168.1.10 with a subnet mask of 255.255.255.0, the first three octets (192.168.1) represent the network portion, while the last octet (10) identifies the specific host within that network.​